This application claims priority of EP Application No. 00810384.8 filed May 5, 2000.
Not Applicable.
1. Field of the Invention
The present invention relates to a timepiece with a mechanism for winding and for correcting at least two indicator members, comprising a winding stem, a pull-out piece engaged, on the one hand, with this winding stem and, on the other hand, with a jumper spring defining three axial positions of the said winding stem, corresponding to those for winding, for correcting at least one indicator member indicating a function derived from time, and for setting the correct time, the said winding stem carrying a winding pinion and a castle wheel engaged with a bar acted upon by a spring and connected to the said pull-out piece to selectively place the said castle wheel in engagement with the said winding pinion and with a minute-wheel geartrain when the said winding stem is in the extreme positions.
2. Description of the Prior Art
Such mechanisms are known and are used in all mechanism timepieces that comprise an indicator indicating a function derived from time, such as the days of the month, the days of the week, the phases of the moon, and the various time zones in particular.
Control of these various functions entails axial movement of the control rod, generally known as the winding stem, into three positions, the first position, that is to say the one in which the winding stem occupies the position in which it is pushed towards the centre of the movement is the usual winding position, one of the two remaining positions is the one for correcting the date or similar derived function, while the other of the remaining positions is the one for setting the correct time.
In general, the winding pinion pivoted on the winding stem is used only for winding when placed in engagement with the castle wheel and the latter is moved axially into the other two positions to come into engagement with a connecting wheel connected alternately to the geartrain for setting the correct time and to the geartrain for setting the date or any other derived function. When the timepiece indicates the days of the month and the days of the week, use is generally made of a bar which, in the correcting position, can move, depending on the direction in which the winding stem is turned, alternately between two angular positions so as to bring the correcting pinion into engagement with the day-of-the-month indicator or with the day-of-the-week indicator. Such correcting mechanisms are described, for example, in GB 1,234,004, in FR 2,169,861 or alternatively in CH 571,734.
One of the problems posed by operating three functions stems from the fact that the winding pinion is used only for winding, which means that the castle wheel has to control two functions. Now, the castle wheel with its two sets of teeth around the edge is the member which, by being moved axially over a portion of non-circular section of the stem makes it possible, in one axial position, to drive the winding pinion in one direction of rotation and, in the other axial position, to come into engagement with the minute-wheel geartrain in order to set the time. This member can thus fulfil two rather than three functions, which means that in three-function mechanisms, instead of coming directly into engagement with the minute-wheel geartrain, the castle wheel comes into engagement with a geartrain designed to be able to be connected alternately with the minute-wheel geartrain or with a geartrain for correcting the day-of-the-month indicator or indicator of some other function derived from time.
In order to switch from one correcting function to the other in these three-function mechanisms, it is therefore necessary to resort to somewhat complicated devices that employ systems involving connecting wheels, reverser pinions and multiple clutches, which may present problems of penetration of the sets of teeth in one another and therefore problems of wear and of bracing.
One of the problems encountered in such mechanisms is that of the winding stem becoming axially jammed when passing from one position to another, if the corrector malfunctions during the change in axial position, which jamming is brought about by the way in which the corrector is operated. Another problem is that of inadvertent correction brought about when the winding stem is moved from one axial position to another.
The object of the present invention is to overcome the aforementioned drawbacks, at least in part.
To this end, a subject of the present invention is a timepiece with a mechanism for winding and for correcting at least two indicator members as defined in claim 1.
Unlike mechanisms of the prior art, the winding pinion controls two functions in succession: winding and correcting the indicator of a function derived from time, so that when the castle wheel is moved axially along the winding stem, it is in order to come into direct engagement with the minute-wheel geartrain. In consequence, the castle wheel of the mechanism for winding, for setting the time and for correcting some other indication derived from time, operates like a conventional castle wheel, remaining in engagement with the winding pinion in two of the three axial positions of the winding stem.
As to the winding pinion, instead of being in engagement with the edge teeth of the winding button, it is simultaneously in engagement with two fixed connecting wheels, themselves meshing with two respective second connecting wheels coaxial with two respective bars which, simply by moving these bars, allow the winding stem to be connected alternately with the winding ratchet wheel or with the corrector for correcting the indication derived from time. Finally, the castle wheel moves only upon the change to the position for setting the time, as in a bar and pull-out-piece conventional two-function winder.
Advantageously, in order to avoid the winding stem becoming jammed as it passes from the winding position to the position for correcting the indication derived from time, the castle wheel is moved into an intermediate axial position so that its teeth are not in engagement either with the winding pinion or with the minute-wheel geartrain.
This arrangement makes it possible to avoid the winding stem becoming jammed axially as it moves from the winding position to the position for correcting the indication derived from time. This operation causes the winding bar to move from the winding position into the position which disengages a reverser pinion carried by this bar and initially in engagement with the winder ratchet subjected, in one direction of rotation, to the tension of the mainspring and immobilized in the other direction of rotation by a retaining pawl. This arrangement also makes it possible, when the winding stem is moved in the opposite direction, to avoid inadvertently correcting the indicator that indicates a function derived from time.